Modification of 137 Cs transfer to rape (Brassica napus L.) phytomass under the influence of soil microorganisms O. Pareniuk a, b, * , K. Shavanova b , J.P. Laceby c , V. Illienko d , L. Tytova e , S. Levchuk b , I. Gudkov d , K. Nanba a a Institute of Environmental Radioactivity, Fukushima University,1 Kanayagawa, Fukushima City, Fukushima Prefecture 960-1296, Japan b Ukrainian Institute of Agricultural Radiology, National University of Life and Environmental Sciences of Ukraine, 7, Mashinobudivnykiv Str., Chabany, Kyivo-Svyatoshin Region, 08162 Kyiv, Ukraine c Laboratoire Des Sciences Du Climat et De l'Environnement (LSCE/IPSL), Unit e Mixte De Recherche 8212 (CEA/CNRS/UVSQ), Gif-sur-Yvette Cedex 91198, France d Radiobiology and Radioecology Dept., National University of Life and Environmental Sciences of Ukraine, Heroyiv Oborony St.,15, Kyiv 03041, Ukraine e General and Soil Microbiology Department, Zabolotny Institute of Microbiology and Virology, NAS of Ukraine,154 Zabolotnoho Str., D03680 Kyiv, Ukraine article info Article history: Received 16 January 2015 Received in revised form 25 June 2015 Accepted 1 July 2015 Available online xxx Keywords: Chernobyl Soil bacteria Plants 137 Сs accumulation abstract After nuclear accidents, such as those experienced in Chernobyl and Fukushima, microorganisms may help purify contaminated soils by changing the mobility of radionuclides and their availability for plants by altering the physical and chemical properties of the substrate. Here, using model experiments with quartz sand as a substrate we investigate the influence of microorganisms on 137 Cs transfer from sub- strate to plants. The highest transition of 137 Cs from substrate to plants (50% increase compared to the control) was observed after Brassica napus L. seeds were inoculated by Azotobacter chroococcum. The best results for reducing the accumulation of 137 Cs radionuclides (30% less) were noted after the inoculation by Burkholderia sp.. Furthermore, Bacillus megaterium demonstrated an increased ability to accumulate 137 Cs. This research improves our prediction of the behavior of radionuclides in soil and may contribute towards new, microbiological countermeasures for soil remediation following nuclear accidents. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Microorganisms play an important role in converting the physicochemical state of substances in soil (Pepper et al., 2008). Depending on the type of soil and microorganism community, these processes may be accelerated or decelerated (Anderson et al., 2003; Simonoff et al., 2007; White et al., 1995). Microorganisms are fundamental to decomposition and related life-cycle processes. To perform these functions, microorganisms may alter the physical and chemical properties of soils, including modifications to the acidity and electrical conductivity of the substrate (Kazy et al., 2006; Wang et al., 2007). These functions can affect the mobility of radionuclides in the soil. For example, the availability of cesium increases with decreased pH (Dumat and Staunton, 1999; Kruyts and Delvaux, 2002). Soil microorganisms, such as bacteria communities, may therefore affect the physical-chemical radionu- clide environment (Niedr ee et al., 2012) and importantly, radio- nuclide availability to plants. The challenge is to predict the effect of soil microflora on radionuclide migration processes, including their influence on plant uptake. This is necessary to understand the contamination of plants within radionuclide contaminated areas. Data on the impact of contamination on soil microbial com- munities is very limited. Tomioka et al. (1992) found that different species have significant differences in their ability to accumulate radionuclides. For example Rhodococcus sp. accumulated signifi- cantly more cesium-137 ( 137 Cs) when grown in a medium, than Pseudomonas sp., that demonstrated no tendency towards accu- mulation. Johnson et al. (1991) reported differences in the ab- sorption of 137 Cs by bacteria, isolated from soil contaminated with radioactive cesium. The different abilities to accumulate cesium ions can be explained by different levels of their affinity with various cations, and the specific transport system in cells. Nevertheless, some physical and chemical factors, including pH, organic matter content and the soil water regime may have a significant impact on the * Corresponding author. Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima City, Fukushima Prefecture 960-1296, Japan. E-mail address: olena.pareniuk@gmail.com (O. Pareniuk). Contents lists available at ScienceDirect Journal of Environmental Radioactivity journal homepage: www.elsevier.com/locate/jenvrad http://dx.doi.org/10.1016/j.jenvrad.2015.07.003 0265-931X/© 2015 Elsevier Ltd. All rights reserved. Journal of Environmental Radioactivity 149 (2015) 73e80